Many athletic shoes used for field sports, such as football, soccer, lacrosse, baseball and softball, have a number of typically truncated cone-shaped cleats for the purpose of increasing traction. Cleats dig into the turf to prevent slipping during starting, stopping, and cutting maneuvers.
However, in addition to providing desirable traction for starting, stopping and cutting, such cleats typically provide very undesirable resistance to pivoting. This can be a disadvantage in at least two ways.
First, the resistance of many prior art cleating arrangements to turning movements can create stresses within the leg when unwanted torque or force is applied to the athlete, particularly to the athlete's leg. Injuries, particularly knee and ankle injuries, can result if a twisting movement is forcibly applied to a leg at a time when the cleats are firmly planted in the turf and release is difficult or impossible.
Second, when pivoting is inhibited, maneuverability of the athlete is limited, thus making performance less than it could be. Enhancing the ability of a player to pivot while still maintaining good traction and foot stability can greatly increase effectiveness on the field.
Recent athletic shoe cleating developments of Michael L. Tanel, the inventor herein, involving annular cleating provided a combination of greatly improved pivotability and excellent traction. These developments tend to reduce the chance of athletic injuries and significantly improve maneuverability on the field. Examples of such cleating are disclosed in U.S. Pat. Nos. 4,577,422, 4,653,206, 4,660,304, 4,669,204, 4,723,365 and 4,748,752.
The improvement in pivotability made possible with shoes in accordance with the principles of such patents is dramatic, and such shoes give the athletes wearing them a natural feeling of freedom together with good feeling of traction for stopping, starting and cutting.
Despite the improvements which these developments represent, additional improvement is needed to provide functional advantages not realized or fully realized in the prior art. Certain conditions and situations must be addressed and are addressed by the improvements of this invention.
One significant concern regarding cleated soles for athletic shoes, including those disclosed in the patents noted above, relates to the degree and ease of penetration of cleats. Ease of penetration has a significant effect on how well a shoe functions. If there is insufficient ground penetration or if ground penetration is difficult, there may be less traction than is desirable and less contact with the turf than is needed for the best possible fixed-position pivoting.
In this regard, consideration must be given to, among other things, the total area of the cleat ends, that is, the total area of the distal surface(s) of the cleat or cleats. Generally speaking, the greater the total end area bearing on the ground, the more difficult it may be for a cleat to penetrate the ground; the smaller the total end area bearing on the ground, the easier it may be for a cleat to penetrate. This effect is accentuated when the ground is hard.
Sharpening the distal end(s) of cleat(s), whether the shoe has discrete cleats or an annular cleat with an annular distal edge, tends to reduce the total area of cleat distal surface. However, it may also cause concern about injury from player contact with such sharp edges. This latter concern particularly arises in the cases of hard plastic or metal cleats.
Whether in pivoting motions or non-pivoting motions, maintenance of stability and traction is important under all conditions. Particular consideration must be given to the traction available from an athletic shoe sole when the wearer is playing on grassy turf with a very compact and hard underlying earth surface. Little if any earth penetration may be possible under such conditions, depending on the extent of turf hardness and compaction. The concern about hard ground under grassy turf is particularly significant when the grass is wet, as often occurs late in the evening or early in the morning because of dew.
The design of the sole can and should address such condition. When penetration is difficult, traction may depend in part on the extent of rubber "grab" on the ground and in part on the extent of "tangle" which is possible with the grass. When the grass is also wet, rubber "grab" is minimized and "tangle" becomes more important to an athlete's traction. Of course, the athlete does not wish to sacrifice pivotability under these conditions any more than he does under other turf conditions.
Another important consideration relates to the degree to which the underlying turf is destroyed when played upon by wearers of cleated shoes. With standard cleating arrangements, when pivoting occurs considerable ground or turf destruction can occur; that is, the turf may be ground up. This is not only harmful to the ground, but in itself causes a loss of foot traction. With an annular cleat, ground destruction is minimized, thus enhancing foot traction. There is a need to have the benefits of both sorts of cleats without unduly destroying turf.
While free pivotability is highly desirable, some athlete's would like there to be a degree of control in such pivotability. Providing a cleating arrangement with a modicum of initial resistance to pivoting would be regarded as desirable by some. However, generally free pivotability beyond that point is considered extremely important. Once again, there is a perceived need for some benefits of annular cleating combined with some benefits of old-style standard cleating arrangements.
Still another concern relates to the strength of cleats. Cleat bending and breakage can be a problem. It is considered very beneficial, of course, for cleats to be highly resistant to bending and breakage. Improvements in cleat structural strength are desirable.
In very soft ground, the lateral profile of some standard cleats of the prior art is sometimes too small to provide a sufficient level of resistance to through-ground sliding. Ground can be displaced when side pressure occurs, thus providing a failure of traction. Providing cleats with greater resistance to such side pressure would be highly desirable.
Still another problem with certain cleated shoes of the prior art is that the pressure of the individual cleats can be felt by the foot of the athlete. Because of this, shoe comfort is reduced. The aforementioned annular cleats tend to overcome this problem, but for shoes with discrete cleats, this problem can be significant.
With all these things in mind, a few more specific observations concerning the prior art are in order.
Shoes like those disclosed in U.S. Pat. No. 4,689,901 (Ihlenburg) tend to have specific problems depending upon what material is used in cleat formation. If, on the one hand, the sole/cleat material is rubber or rubber-like in its surface characteristics and resiliency, such shoes are susceptible to the aforementioned problems of cleat bending and breakage because the cleats are of slight dimension (thin ridges) at positions too near the main sole surface, not to mention the problem of short life because of excessive early wearing-away of such material. If, on the other hand, the sole/cleat material is a hard synthetic material, such shoes, quite unlike shoes of rubber or rubber-like material, will be seriously deficient in their ability to engage certain playing surfaces.
At least one major manufacturer of cleated footwear has recognized such problems, particularly the problem of bending, breakage and excessive wearing-away of rubber or rubber-like cleat material. The Nike.TM. Shark.TM. shoe has spaced rubber or rubber-like cleats with substantial structural supports or ramping molded onto their inner sides to prevent bending, breakage and excessive wear. While such structure serves to prevent bending, breakage and excessive wear, such structure does not even begin to address many of the other problems and needs mentioned above, particularly those related to pivotability.
It was in this technical context and state of the art that the instant invention was made, overcoming all of the problems, conflicting and otherwise, which are discussed above.
A few general comments are in order before turning to a description of this invention. In particular, a brief description of the foot and its pivoting and planted positions will be helpful. This can serve as an aid in understanding preferred embodiments of this invention.
The sole of the foot includes four portions. These are, in order from back to front: the heel portion; the arch portion; the ball-of-the-foot portion; and the toe portion. The heel and ball-of-the-foot portions are those portions which share most if not all of the player's weight when the player is in a normal standing position with feet generally flat on the ground. In such position, the arch portion and toe portion bear little if any weight.
When a player is "on his toes" in a "ready" position, virtually all of the player's weight is normally shared by the toe portion and the ball-of-the-foot portion. The same is usually true when a player is "digging" in a running action. Indeed, when a player is in the ready position, the juncture of the phalanges (toe bones) and the metatarsals is the center of weight bearing. In other words, the center of weight bearing in the forward portions of the foot actually moves forward when a player shifts to the ready position.
The sole of an athletic shoe has portions immediately below these four portions of the foot which may be designated, and herein are designated, by the same terms.